From: Hayes Wang <hayeswang@realtek.com>
To: David Miller <davem@davemloft.net>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
nic_swsd <nic_swsd@realtek.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: RE: [PATCH net v2 0/4] r8152: fix scheduling napi
Date: Thu, 26 Jan 2017 03:04:45 +0000 [thread overview]
Message-ID: <0835B3720019904CB8F7AA43166CEEB201A13865@RTITMBSV06.realtek.com.tw> (raw)
In-Reply-To: <20170125.143119.411717735878453521.davem@davemloft.net>
David Miller [mailto:davem@davemloft.net]
> Sent: Thursday, January 26, 2017 3:31 AM
[...]
> I think the fundamental issue is that since you can't stop URBs from
> queueing up, you cannot properly synchronize NAPI and schedule polling
> properly.
>
> From my perspective what happened here is you want GRO support, but it
> comes at the expense of this extremely racey NAPI support which does
> not at all achieve one of the main advantages of NAPI which is
> interrupt mitigation.
May you apply these patches first, until I find another way to replace
current one? The driver uses NAPI now and I have no idea to find better
way to replace current one. I think it would take me long time to find
out the solution. And the issue is still there until I finish this work.
If now I give up the NAPI and its advantages except for the interrupt
mitigation, some things would become worse.
Our hw supports packet aggregation. The purpose is interrupt mitigation,
too. I wouldn't say it is better than what the NAPI does. However, I
could say we try to improve it. If the interrupt could be disabled, I
would be happy to do it. However, it is the limitation of USB devices.
That is why I still use NAPI even though the interrupt cannot be disabled
for USB devices. Because one of the advantages of NAPI couldn't be
satisfied, I must not use the NAPI. Doesn't it seem too strict?
Best Regards,
Hayes
next prev parent reply other threads:[~2017-01-26 3:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-25 2:50 [PATCH net 0/4] r8152: fix scheduling napi Hayes Wang
2017-01-25 2:50 ` [PATCH net 1/4] r8152: avoid start_xmit to call napi_schedule during autosuspend Hayes Wang
2017-01-25 5:02 ` Stephen Hemminger
2017-01-25 2:50 ` [PATCH net 2/4] r8152: avoid start_xmit to schedule napi when napi is disabled Hayes Wang
2017-01-25 2:50 ` [PATCH net 3/4] r8152: re-schedule napi for tx Hayes Wang
2017-01-25 2:50 ` [PATCH net 4/4] r8152: check rx after napi is enabled Hayes Wang
2017-01-25 8:13 ` [PATCH net v2 0/4] r8152: fix scheduling napi Hayes Wang
2017-01-25 8:13 ` [PATCH net v2 1/4] r8152: avoid start_xmit to call napi_schedule during autosuspend Hayes Wang
2017-01-25 8:13 ` [PATCH net v2 2/4] r8152: avoid start_xmit to schedule napi when napi is disabled Hayes Wang
2017-01-25 8:13 ` [PATCH net v2 3/4] r8152: re-schedule napi for tx Hayes Wang
2017-01-25 13:57 ` Eric Dumazet
2017-01-26 1:22 ` Hayes Wang
2017-01-25 8:13 ` [PATCH net v2 4/4] r8152: check rx after napi is enabled Hayes Wang
2017-01-25 19:31 ` [PATCH net v2 0/4] r8152: fix scheduling napi David Miller
2017-01-26 3:04 ` Hayes Wang [this message]
2017-01-26 3:46 ` David Miller
2017-01-26 1:38 ` [PATCH net v3 " Hayes Wang
2017-01-26 1:38 ` [PATCH net v3 1/4] r8152: avoid start_xmit to call napi_schedule during autosuspend Hayes Wang
2017-01-26 1:38 ` [PATCH net v3 2/4] r8152: avoid start_xmit to schedule napi when napi is disabled Hayes Wang
2017-01-26 1:38 ` [PATCH net v3 3/4] r8152: re-schedule napi for tx Hayes Wang
2017-01-26 1:38 ` [PATCH net v3 4/4] r8152: check rx after napi is enabled Hayes Wang
2017-01-26 3:47 ` [PATCH net v3 0/4] r8152: fix scheduling napi David Miller
2017-01-26 3:52 ` Hayes Wang
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